CHAPTER 17

Nutritional Assessment of Patients with Respiratory

Disease

Nutritional Status

Major factor influencing acute and long term outcomes

Quantity and quality of food affects the efficiency of the metabolic process

Nutrients can enhance or harm immune functions

Important to understand the interdependence of nutrition and respiratory care

Integration of Organ Systems

Components of the Respiratory System

Neurologic Drives and controls

ventilation Requires glucose,

protein

Respiratory Muscles Pump that drives the

lungs Energy from glucose,

fatty acids, muscle glycogen

Cardiovascular Carries both nutrients

and oxygen to the tissues

Protein, carbohydrates, fat, water, vitamins

Gas Exchange V/Q matching Surfactant synthesis,

humidity and mucociliary performance

Metabolism

Produces body heatRequires fuel = foodCombustion requires

oxygen to produce ATP

CatabolismAnabolism

4 major phases Digestion Production of acetyl

CoA Krebs/citric acid cycle ATP production

Metabolism

Metabolic rates of the tissues dictate the amount of oxygen needing to be picked up in the lungs

BMR/BEEREE

Sufficient food maintains an equilibrium – energy production and demands of environment

Too little food ingested – use of stored energy

Too much food ingested – convert and store as fat

Too much or too little cause the functional capability to decrease

Energy Use

Determined by: Direct calorimetryIndirect calorimetry

Respiratory measurements

Metabolic Cart

Bedside monitors O2 CO2 analyzers; flow

transducers Nose clips/Mouthpiece Hood/Tent Through the ventilator

circuit

Weir Equation Determines energy

expenditure

Procedure: Collect expired gas Analyze for carbon

dioxide and oxygen Measure the volume of

gas collected Calculate VCO2 and

VO2 and convert to kilocalories

Monitoring incorporated into existing Hardware

In order to provide an accurate breath-by-breath measurement of respiratory gas exchange the module must algorithmically integrate side stream gas concentrations (CO2 and O2) as well as the flows and volumes generated by each breath. This is done with the D-Lite + flow sensor in conjunction with the fast paramagnetic oxygen sensor and the infrared gas bench for CO2 measurement. Thus, the measurement can be thought of as a three stage technique whereby flows and concentrations are synchronized and gas volumes calculated.

Variations in oxygen consumption and carbon dioxide production (expressed as percent change) associated with diagnostic and therapeutic interactions in an ICU patient.

Clinical Usefulness of Metabolic Monitoring

Determines the REEGuides appropriate

nutritional supportTailor support to

meet the patient’s needs

Continued evaluation of adequacy and appropriateness of nutritional support

Provides relationship between DO2 (oxygen delivery) and VO2

(oxygen consumption)Guide for ventilator

mode and setting selection, assess weaning strategies; predictor of patient outcomes

Limitations

No contraindications other than caution when assembling equipment (brief interruption of mechanical ventilation while connecting measurement lines – hypoxemia, bradycardia)

Leaks in the system prevent accurate measurements\

Patient condition or activities may prevent measurements from occuring

Costly equipment with few comprehensive studies demonstrating improved outcomes, decreased ventilator times, or shorter ICU/hospital stays

EnteralEnteral ParenteralParenteral

Preferred route Sites

Nasogastric, nasoduodenal nasojejunal

Gastrostomy Jejunostomy Esophagotomy PEG/PEJ

Given by bolus, intermittent, or continuous drip

Risk of Aspiration

Use peripheral or central vein

TPNRisk of infection

Routes of Nutritional Administration

Nutritional Depletion

Blood sugar levels; gluconeogenesisProtein depletionDecrease in respiratory muscle strengthWeight lossMalnutritionPEM

Nutritional Repletion

Hindered in Respiratory patientsRespiratory response is usually regulated by

VCO2 Critical care patients require continuous

assistance with nutrition and breathing

Respiratory Quotient

Metabolic pathways use O2 produce CO2

RQ = ratio of VCO2 to VO2

Determined by the amount of fat, carbohydrate, or protein eaten

PROTEIN RQ = 0.85FAT RQ = 0.7CARB RQ = 1.0Mixture = 0.8

Minimum nutrient levels to avoid deficiency symptoms and low enough to prevent toxicity

Nutritional Elements

Carbohydrate Largest amount of

intake Complex vs simple Evaluate response –

CO2 load and production

Protein 12-15% intake Quantity and quality Extremes are

detrimental Nitrogen balance

Fat Best storage form for

energy Efficient way to provide

calories Quality – saturated,

polyunsaturated, monounsaturated

Vitamin, Mineral, Other Variety of foods Supplementation

Fluids, Electrolytes Monitor intake/output

The role of the RT in nutrition

NOT responsible for the nutritional assessment

Familiar with the process and contribute to the data gathering History Physical exam Clinical lab values

Respiratory Assessment

Inspection BMI

Cachectic Kwashiorkor/Marasmus Obesity Muscle condition JVP, acites, edema –

fluid balance Sputum viscosity

Auscultation Course or fine crackles Wheezing

Laboratory Findings PFT measurements PEP, PIP Lung compliance ABG values